The glycolytic and lipid metabolism of epidermis will be examined in relation to differentiation and cornification of the epidermis. To provide models for the various stages of differentiation from germinative to horny cells, organ culture of fetal skin will be employed. Cultures will be grown in media supplemented in various ways to produce replicating and differentiating epidermis. Metabolism of glucose and patterns of lipogenesis will be assessed at various stages of differentiation and related to selective synthesis of proteins, mitotic activity and morphology.